The discharge profile of some batteries can be very flat and then drop suddenly at end-of-life (EOL). Such a sudden voltage drop does not allow enough time for device replacement between the impending EOL and actual loss of power to the device. This is especially critical when such a battery is used in an implantable medical device. Because of the lack of an accurate capacity gauge it is not uncommon to sacrifice up to 25% of the capacity of a battery to ensure that the battery is working until the time for explant. As a result, there is a need for batteries that provide a more accurate indication of remaining battery life.